FREQUENCY SYNTHESIZER FOR ACHIEVING FAST RE-LOCK BETWEEN ALTERNATE FREQUENCIES IN LOW BANDWIDTH PLLS

摘要

A frequency synthesizer that includes a reference frequency scaler and a phase locked loop (PLL) coupled to the reference frequency scaler. The reference frequency scaler is configured to generate a first reference frequency and a second reference frequency. The PLL is configured to generate a first output frequency based on the first reference frequency during a first timeslot and a second output frequency based on the second reference frequency during a second timeslot. The PLL comprises a loop filter that includes a first switch connected in series to a first capacitor and configured to close during the first timeslot and a second switch connected in series to a second capacitor and configured to open during the first timeslot.